JPH0779407A - Digital video signal recording / reproducing device - Google Patents

Abstract

(57) [Abstract] [Purpose] PALplus without PALplus decoder
It enables recording of plus-type television signals. A Y signal, a U signal, a V signal separated by a Y / C separation circuit 42 and a helper signal demodulated by a helper signal demodulator 43 are supplied to a recording / reproducing system 4.
The recording / reproducing system 4 outputs the Y signal, the U signal, and the V signal 4: 2: 0.
A / D conversion is performed by the component encoding method of
Further, the data is compressed and recorded by DCT and variable length coding. The helper signal is, for example, 6.75 MH.
z, 4 bits are quantized and recorded. A helper signal
It may be boosted by 6 dB before the / D conversion, and data-compressed and recorded together with the Y signal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital video signal recording / reproducing apparatus for converting a PALplus television signal into digital data for recording.

[0002]

2. Description of the Related Art A digital VTR for A / D converting an analog video signal and compressing a data amount for recording has been proposed. FIG. 7 is a block diagram showing an example of a video signal recording / reproducing system in such a digital VTR. First, the digital VTR will be described with reference to this figure.

An input analog component video signal (Y, U, V) is converted into a digital component video signal by an A / D converter 11, and a blocking circuit 12 converts 8 samples in the horizontal direction and 8 lines in the vertical direction (hereinafter, 8 lines). X8 units) are combined into one block, and four Y signal blocks, U
A macro block is composed of a total of six blocks, one for each of the signal and V signal, and shuffled and Y / C multiplexed in macro block units. The 8 × 8 unit data is discrete cosine transformed by the DCT circuit 13, and the time amplitude domain data is transformed into the frequency domain data. The data obtained by the discrete cosine transform is the encoder 1
4 is requantized, variable-length coded by a two-dimensional Huffman code or the like, and data compressed. In this case, the step width in the requantization is set so that the total data amount for each buffering unit composed of a predetermined number of macroblocks (eg, 5 macroblocks) does not exceed a certain amount. Next, in the framing circuit 15,
A plurality of such buffering units are arranged vertically to form a frame.
CC (Error Correction Code)
After adding the parity of the product code configuration, the channel encoder 17 converts the parity into serial data and records it on a magnetic tape (not shown).

At the time of reproduction, the channel decoder 18 performs data detection and serial / parallel conversion, and ECC
The circuit 19 performs error correction. The error-corrected data is decomposed into word units of variable-length code by the deframing circuit 20, decoded and dequantized by the decoder 21, and inverse discrete cosine transformed by the inverse DCT circuit 22 to obtain data of 8 × 8 unit. Become. This data is subjected to deshuffling, Y / C separation, data interpolation, etc. by the deblocking circuit 23 to be returned to the digital component video signal, converted to the original analog component video signal by the D / A converter 24 and output. .

In practice, the U signal and the V signal are input / output on different signal lines, but in this specification, they are described as one signal line for the sake of convenience.

A digital VTR constructed in this way
For example, when a PAL video signal is recorded by 4: 2: 0 component coding, as for the Y signal, as shown in FIG. Since data of 576 samples in the direction is processed, 90 blocks of 8 × 8 units are arranged in the horizontal direction and 72 blocks in the vertical direction. Similarly, as for the U signal and the V signal, as shown in FIG.
Since 0 sample data and 288 sample data in the vertical direction are processed, 45 blocks of 8 × 8 units are arranged in the horizontal direction,
36 pieces are lined up in the vertical direction. And FIG. 8 (c)
As shown in FIG. 5, a macro block is composed of a total of 6 blocks, each of which is a block of four Y signals and one block of U and V signals.

When such a macroblock is viewed on the entire screen of one frame, as shown in FIG. 9, there are a total of 1620 macroblocks, 45 in the horizontal direction and 36 in the vertical direction.

Then, as shown in FIG. 10, the video data of the 1620 macroblocks is recorded on 12 tracks, and thus the video data of 135 macroblocks per track is recorded on the diagonal tracks T0 to T0 of the magnetic tape MT. Record at T11.

As the EDTV standard in Europe, the current P
PALplus that achieves a wider screen while maintaining compatibility with the AL system (Compatibility)
A scheme has been proposed. First, an outline of the PALplus system will be described with reference to FIGS. 11 and 12.

FIG. 11 shows an image from a PALplus system source to a receiver. First, the source has 720 effective horizontal samples as shown in (a),
The number of effective scanning lines in the vertical direction is 576 (however, this is the case of the Y signal, the number of effective samples in the U direction and V signal is 360 in the horizontal direction), and the image signal has an aspect ratio of 16: 9. .

This image signal is subjected to a thinning-out process for every four vertical lines, and as shown in (b), the main image in which the vertical scanning lines are reduced to 432 lines. Converted to a signal. Then, the Y signal component of the thinned scanning line forms a difference signal with the average level of the scanning lines above and below, and it is used as a helper signal as shown in (c).
As shown in (d), the main image signal and the helper signal are transmitted as an image signal having an aspect ratio of 4: 3 by the letterbox method in which the helper signal is multiplexed above and below the main image signal. At this time, an identification code indicating that the signal is a PALplus system signal is inserted in the vertical blanking period of the image signal.

On the image receiving side, when an image is received by a current PAL type image receiver which does not have a PALplus type decoder, as shown in (e), there are 432 scanning lines corresponding to the main image signal. Helper signals are displayed above and below the image. However, this helper signal is low level, has a high frequency component, and is not conspicuous because it is at the edge of the screen.

On the other hand, when an image is received by a receiver equipped with a PALplus type decoder, the identification code is detected and P is detected.
The signal of the ALplus system is identified, and the signal of the scanning line thinned out on the image transmitting side is created based on the helper signal. Then, since the original 576 scanning lines are restored,
An image having an aspect ratio of 16: 9 having 576 scanning lines is displayed as in (f).

FIG. 12A is a block diagram showing a PALplus encoder. First, the Y signal, the U signal, and the V signal signal are input to the let-back processing circuit 31. Here, one scanning line is thinned out every four lines, and as shown in FIG.
The signal of (b) is supplied to the PAL encoder 32. The helper signal shown in FIG. 11C is supplied to the helper signal modulator 33.

The PAL encoder 32 has a 4.43 MH
The z subcarrier is supplied and creates a PAL television signal. The helper signal modulator 33 is also supplied with a 4.43 MHz subcarrier, and VSB modulation is performed by the helper signal.

The output of the PAL encoder 32 and the output of the helper signal modulator 33 are output by the synthesizing circuit 34 as shown in FIG.
As shown in (d), the PALplus system television signal is synthesized and transmitted.

FIG. 12B is a block diagram showing a PALplus system decoder. First, the PALplus system television signal is separated by the separation circuit 41 into the modulated helper signal and the PAL system main image signal. Then, the modulated helper signal is demodulated into a helper signal by the helper signal demodulator 43 and supplied to the inverse letterbox processing circuit 44. Also, PA
The L-type main image signal is output by the Y / C separation circuit 42 to Y
Reverse letterbox processing circuit 44 separated into U and V signals
Is supplied to. The inverse letterbox processing circuit 44 creates scanning lines thinned out on the image transmitting side, restores 576 scanning lines as shown in FIG. Since the helper signal does not include the U signal component and the V signal component,
The U and V signals are restored from the upper and lower scanning lines.

[0018]

[Problems to be Solved by the Invention] Such PALpl
When a us television signal is recorded on a digital VTR, a PALplus television signal is decoded by the PALplus decoder shown in FIG. 12B to create an analog component video signal, which is input to the recording system shown in FIG. It is possible to do it.

However, with such a configuration, there is a problem that the circuit scale of the digital VTR becomes large because it is necessary to provide the PALplus decoder in the digital VTR.

The present invention has been made to solve the above problems, and provides a digital video signal recording / reproducing apparatus capable of recording a PALplus system television signal without providing a PALplus decoder. The purpose is to

[0021]

In order to solve the above-mentioned problems, the invention according to claim 1 is a device for converting a PALplus system television signal into digital data and recording the digital signal. Means for demodulating the helper signal from the second means, second means for converting the helper signal demodulated by the second means into uncompressed digital data, and PALplus.
Third means for converting the main image signal separated from the television signal of the system into compressed digital data, and the output of the second means and the output of the third means are recorded in another area of the recording medium. And means.

The invention according to claim 2 is the PALpl.
In a device for converting a television signal of a us system into a digital signal and recording the digital signal, first means for demodulating a helper signal from the television signal of the PALplus system,
Second means for amplifying the helper signal demodulated by the first means, and third means for converting the main image signal separated from the output of the second means and the PALplus system television signal into compressed digital data. And a fourth means for recording the output data of the third means on a recording medium.

[0023]

According to the invention of claim 1, PALplus is used.
Only the helper signal is demodulated from the system television signal,
Convert to uncompressed digital data. Also,
The main image signal separated from the PALplus television signal is converted into compressed digital data.
Then, the uncompressed digital data and the compressed digital data are recorded in different areas of the recording medium.

According to the invention of claim 2, PALpl
Only the helper signal separated from the us television signal is demodulated and amplified. Then, the main image signal separated from the PALplus television signal is converted into compressed digital data and recorded.

[0025]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a schematic block diagram of a video signal processing system of a digital video signal recording / reproducing apparatus according to an embodiment of the present invention. In this figure, FIG.
The same numbers are given to the portions corresponding to.

In FIG. 1, the PALplus type television signal output from the tuner 1 is separated by the separation circuit 4.
1 separates the main image signal and the helper signal, the main image signal is supplied to the Y / C separation circuit 42, and the helper signal is supplied to the helper signal demodulator 43. The main image signal is separated into Y, U and V signals by the Y / C separation circuit 42, the Y signal is supplied to the switching circuit SW, and the U signal and the V signal are supplied to the recording / reproducing system 4. The helper signal is demodulated by the helper signal demodulator 43, and the switching circuit S
Supplied to W. Y supplied to the switching circuit SW
The signal and the helper signal are switched at a predetermined timing and supplied to the recording / reproducing system 4. The recording / reproducing system 4 digitizes the input Y signal, U signal, V signal and helper signal and records and reproduces them (details will be described later).

As described above, in the present invention, PALplus is used.
The system television signal is not completely decoded and only the helper signal is demodulated and supplied to the recording / reproducing system 4.
In the Lplus decoder, the inverse letterbox processing circuit 44 having a large circuit scale becomes unnecessary.

Next, the structure of the recording / reproducing system 4 will be described. (First Embodiment) FIG. 2 is a block diagram of a first embodiment of a recording / reproducing system. Here, the same numbers are assigned to the parts corresponding to those in FIG. 7.

In this figure, the Y signal and the helper signal are converted into the A / D signal by the first switching circuit SW1.
The helper signal supplied to the converter 11 is supplied to the A / D converter 2
It is distributed so as to be supplied to No. 5. Further, the U signal and the V signal are supplied to the A / D converter 11.

Y signal, U supplied to the A / D converter 11
The processing until the signal and V signal are output from the encoder 14 is basically the same as that in the case of FIG. On the other hand, the helper signal is converted into a digital signal in the A / D converter 25 with a sampling frequency lower than the Y signal component of the main image signal and a small number of bits (eg, 6.75 MHz, 4 bits) and stored in the memory 26. To be done.

The output of the encoder 14 and the output of the memory 26 are input to the framing circuit 15 via the second switching circuit SW2. In the framing circuit 15, the buffering unit output from the encoder 14 and the digitized helper signal output from the memory 26 (hereinafter referred to as a digital helper signal).
And are framed according to the track format described later. At this time, the ID code extracted from the vertical blanking period of the PALplus system television signal is added to the buffering unit. The output of the framing circuit 15 is added with the parity of the product code configuration in the parity generation circuit 16, and then the channel encoder 17
To convert it to serial data and record it on a magnetic tape.

The blocking operation and track format in this embodiment will be described. When the main image signal is recorded by 4: 2: 0 component encoding, the Y signal has data of 720 samples in the horizontal direction and 432 samples in the vertical direction per frame, as shown in FIG. Is processed, so 8 ×
90 blocks of 8 units horizontally, 54 blocks vertically
It will be lined up individually. Similarly, as for the U signal and the V signal, as shown in FIG. 3B, data of 360 samples in the horizontal direction and 216 samples in the vertical direction are processed per frame, so that 8 × 8 units of data are processed. 45 blocks are arranged in the horizontal direction and 27 blocks are arranged in the vertical direction.

As in the case of FIG. 8C, when a macro block is composed of a total of 6 blocks, 4 blocks for the Y signal and 1 block for the U signal and V signal, the entire screen of one frame is composed. As shown in FIG. 4, there are a total of 1215 macroblocks, 45 in the horizontal direction and 27 in the vertical direction.

Comparing this with the case of FIG. 9, there are 405 macroblocks in one frame and 33.
Since there are 75 macroblocks left, the digital helper signal is recorded in this portion.

FIG. 5 shows an example of the track format. In this pattern, the main image signal is recorded on the entrance side of the track and the digital helper signal is recorded on the exit side. However, since it is necessary to arrange an integer number of macroblocks for each track, recording is performed so that 12 tracks have 1215 macroblocks.

As another example of the track format,
For example, out of 12 tracks, predetermined 9 tracks (eg,
It is also possible to record the main image signal on T0 to T8) and record the digital helper signal on the remaining three tracks (eg, T9 to T11).

Next, the sampling frequency and the number of bits of the main image signal and the helper signal will be described. In the digital VTR of FIG. 7, the Y signal is 13.5 MHz.
The z, U and V signals are sampled at 6.75 MHz and quantized with 8 bits each. Then, the video data digitized in this way can be processed at about 25 Mbp.
Compress and record to s. Therefore, in this embodiment, 25
6.25 Mbps, which is ¼ of Mbps, can be assigned to the digital helper signal. The helper signal is 6.75 MH, which is half the sampling frequency of the Y signal.
When sampling is performed with z and quantized with n bits,
(720/2) × (576/4) × n × 30≈n × 1.
It will be 56 Mbps. Therefore, it is possible to quantize and record with n = 4 bits.

The thus recorded data is subjected to data detection and serial / parallel conversion by the channel decoder 18, error correction is performed by the ECC circuit 19, and is supplied to the deframing circuit 20. The deframing circuit 20 decomposes the buffering unit into word units of the variable length code, and outputs the third switching circuit SW3.
To the decoder 21 via. Further, the deframing circuit 20 supplies the digital helper signal to the memory 27 via the third switching circuit SW3.

The data supplied to the decoder 21 is shown in FIG.
In the same manner as in the above case, the data is decoded and inversely quantized, and the inverse DCT circuit 22 performs the inverse discrete cosine transform to obtain 8 × 8 unit data. This data is subjected to deshuffling, Y / C separation, data interpolation, etc. by a deblocking circuit 23 to be returned to a digital component video signal, and D / A
The converter 24 converts the original analog component video signal (Y, U, V) and outputs it. Then, in the adder 29, PALpl separated from the reproduced data
The ID for identifying the us method is reinserted in the vertical blanking period of the Y signal.

On the other hand, the digital helper signal stored in the memory 27 is read out at a predetermined timing and D /
It is converted into the original helper signal by the A converter 28.

Y signal and D / A output from the adder 29
The helper signal output from the converter 28 is output via the fourth switching circuit 4. Also, U signal and V
The signal is directly output from the D / A converter 28.

As described above, in this embodiment, since the helper signal is recorded and reproduced without being compressed, the helper signal is not subjected to quantization distortion.

(Second Embodiment) FIG. 6 is a block diagram of a second embodiment of the recording / reproducing system. Here, parts corresponding to those in FIG. 1 are assigned the same numbers.

In this embodiment, the Y signal and the helper signal are input to the A / D converter 11 via the boost-amplifier 31. The boost-amplifier 31 is configured to amplify, for example, 6 dB by the control signal only during a period when the helper signal is input. The Y signal, helper signal, U signal and V signal input to the A / D converter 11 are processed and recorded in the same manner as in the case of FIG. Therefore, in this embodiment, the helper signal is also compressed, encoded, and recorded together with the Y signal and the like. In this embodiment as well, as in the first embodiment, in the framing circuit 15, an ID for identifying the PALplus system is added to the buffering unit.

At the time of reproduction, the same processing as in the case of FIG. 7 is performed,
From the D / A converter 24, Y signal, helper signal, U signal,
The V signal is output. Then, as in the first embodiment, the PALpl separated from the reproduced data is added by the adder 29.
The ID for identifying the us method is reinserted in the vertical blanking period of the Y signal. The output of the adder 29 is output via the attenuator 32. The attenuator 32 uses the boost-amplifier 3 only during the period when the helper signal is input by the control signal.
It is configured to attenuate only the amount amplified by 1.

As described above, in this embodiment, since the level of the helper signal, which is a low level signal, is increased, it is possible to prevent the helper signal from undergoing quantization distortion in the DCT circuit. Further, the recording / reproducing system from the A / D converter 11 to the D / A converter 24 has no special difference from the PAL system shown in FIG.
It is easy to use in common with the AL type digital VTR.

[0047]

As described above in detail, according to the present invention, since only the helper signal is demodulated and recorded, P
It is possible to record a PALplus system television signal without providing an ALplus decoder.

Further, since the helper signal is recorded without data compression, or after being amplified and then data-compressed, the helper signal can be recorded without undergoing quantization distortion due to compression. Therefore, when the recording medium is reproduced, PALplus is
A good image can be reproduced even if the s-system signal is decoded.

[Brief description of drawings]

FIG. 1 is a schematic block diagram of a video signal processing system of a digital video signal recording / reproducing apparatus according to an embodiment of the present invention.

FIG. 2 is a block diagram of a first embodiment of a recording / reproducing system in an embodiment of the present invention.

FIG. 3 is a diagram showing a blocking operation in the embodiment of the present invention.

FIG. 4 is a diagram showing a macroblock of one screen of a main image in the embodiment of the present invention.

FIG. 5 is a diagram showing an example of a track format in the embodiment of the present invention.

FIG. 6 is a block diagram of a second embodiment of a recording / reproducing system.

FIG. 7 is a block diagram showing an example of a video signal recording / reproducing system in a conventional digital VTR.

FIG. 8 is a diagram showing a blocking operation in a conventional digital VTR.

FIG. 9 is a diagram showing a macroblock of one frame in a conventional digital VTR.

FIG. 10 is a diagram showing a track format in a conventional digital VTR.

FIG. 11 is a diagram showing an image from a PALplus system source to a receiver.

FIG. 12 is a block diagram showing a PALplus encoder and a decoder.

[Explanation of symbols]

11, 25 ... A / D converter, 12 ... Blocking circuit,
13 ... DCT circuit, 14 ... Encoder, 15 ... Framing circuit, 26 ... Memory, 31 ... Boost amplifier, 43
... Helper signal demodulator

Claims (2)

[Claims] 1. (a) First means for demodulating a helper signal from a PALplus television signal,
(B) second means for converting the helper signal demodulated by the first means into uncompressed digital data, and (c) the main image signal separated from the PALplus television signal is compressed. Digital video comprising: third means for converting the digital data into digital data; and (d) means for recording the output of the second means and the output of the third means in another area of the recording medium. Signal recording / reproducing device. 2. A first means for demodulating a helper signal from a PALplus television signal,
(B) second means for amplifying the helper signal demodulated by the first means, and (c) compression of the main image signal separated from the output of the second means and the PALplus television signal. A digital video signal recording / reproducing apparatus comprising: a third means for converting the digital data into a digital medium, and (d) a fourth means for recording the output data of the third means on a recording medium.